Research: Over 5 million people are at risk for developing grain dust related respiratory illness in the United States and Canada. Inhalation of grain dust can result in airflow abnormalities acutely, and pulmonary health impairment chronically. Moreover, acute changes predict the development of long-term abnormalities. The overall goal of this project is to investigate the acute physiologic responses that occur in the lungs of humans exposed to grain dust, and their biological correlates. Crossover studies will be done on naive subjects to compare the effects of inhalation challenge with buffered saline to extracts of corn dust in doses which are analogous to the amount of dust inhaled by workers during a day in the work environment. Changes in airflow, lung volume and gas exchange will be measured before and after inhalation challenge. The inflammatory response will be evaluated in different anatomic regions of the lung using bronchoscopy with lavage procedures which will sample the parenchyma, small, and large airways separately. Lavage fluid cellularity, cytokine levels, and corresponding cellular mRNA levels from these different regions will be correlated with changes in pulmonary function. Similar protocols will be used to evaluate the impact of individual host factors such as ethnic background, atopy, asthma, smoking, and gender. Further investigation will examine the effects of repeated exposure, and the development of tolerance. Environment: The University of Iowa is a unique environment in which high quality research training in Pulmonary Medicine, Occupational Medicine, and Epidemiology are readily available. Drs. Schwartz, Merchant and Hunninghake are nationally recognized experts in occupational lung diseases, and the Department of Internal Medicine and the Pulmonary Division are highly committed to creating the environment and providing the resources necessary for success in clinical and basic investigation. Collaboration with the departments of Preventive Medicine and Environmental Health, and Radiology, as well as access to the most current cellular and molecular techniques creates unique opportunities to study occupational lung diseases at all levels. This incomparable situation will allow the candidate to pursue his research and career goals in very favorable circumstances.